Like many of you out there i have been watching lots of HD movies with VLC and got the "computer to slow message," i think its because of the MKV container VLC dosnt seem to like it to much, anyways this is what i did, original video was an mkv X264 1080p 20.45 mbits/s pretty crazy and VLC just wouldnt cut it, so i tried the Perian codec for mac this allowed me to open MKV's in Quicktime Pro [ it takes awhile to load which isnt so great and the playback also wasnt so great] so all i did was file-save self contained movie an what do you know pristine playback of a perfect 1080p movie. i guess changing the container helped greatly.
i forgot i also installed the avc1 decoder codec for QT and the MP4v decoder, which you can find on the apple website, i dont know if they hare helping but its worth a try.
hope this helps
toodles
